Modified phenolic resin system and laminates made therefrom

ABSTRACT

A laminate, that can be used as an exterior, refinishable surface for snow skis, comprises a plurality of plastic resin impregnated bonded paper sheets, each having been impregnated with a solution of a melamine-formaldehyde, phenol-formaldehyde resinous admixture which contains from about 10 to 70 weight percent melamine-formaldehyde resin solids based on phenolformaldehyde resin solids.

United States Patent Palazzolo et al. [4 1 Dec. 26, 1972 1 1 MODIFIED PHENOLIC RESIN SYSTEM .6 3,070,572 12/1962 01811116161. ..260/839 AND LAMINATES MADE THEREFROM FOREIGN PATENTS 0R APPLICATIONS [72] Inventors: Salvatore E. Palazzolo, Hampton;

1 o Mccaskey, Allendale 390,760 8/1965 Switzerland ..280/11.13 L both of 1,299,263 6/1962 France ..2so/11.13 LM 1,457,826 9/1966 France ..280/1l.l3 L [73] Assignee: Westinghouse Electric Corporatio Pittsburgh, 1 Primary Examiner-Benjamin Hersh 22 d: 9 Assistant Examiner-Milton L- 1 Attorney-F. Shapoe, A. Mich, Jr. and o. 1 01116 [21] Appl. No.: 1,749

. [57] v ABSTRACT Cl "Fm L, 2 6 39 A laminate, that can be used asan exterior, refinisha- [51] lnt.Cl....- 5/12 2 w u f v for-snow-iskis, comprises, plurality f [58] Field of Search.....-280/l 1.13; 161/246; 260/839 plastic resin impregnated bonded paper sheets, each havingv been impregnated with a solution of a [56] Rderences C'ted melamine-formaldehyde, phenol-formaldehyde UNITED STATES PATENTS resinous admixture which (:ontains from about 10 to v 70 weight percent melamine-formaldehyde resin solids 2,331,744 10/1943 Swain et al. ..260/19 based on phenol-formaldehyde resin solids. 2,801,198 7/1957 Morris et al......

2,387,256 10/1945 Groten 12 Claims, 2 Drawing Figures PATENTED i972 3.707.296

FIGZ.

WITNESSES INVENTORS Salvatore E. Polozzolo 0nd Harold 0. Mc Coskey,Jr.

MODIFIED PHENOLIC RESIN SYSTEMAND LAMINATES MADE THEREFROM BACKGROUND OF THE INVENTION thickness. The sidewall thickness is usually one-eighth inch thick.

'The primary requirements for these laminates are I that they must'be refinishable after being nicked or scratched, water resistant, heat resistance and flexible enough to withstand the ski manufacturers process before and after fabrication. Most of the high pressure laminates being used meet all the physical properties required except refinishability-jMost of the laminates upon refinishing show laminations within the laminate as objectionable lines.

SUMMARY OF THE INVENTION We have found a melamine modified, phenolic resin that when cured, properly possesses excellent refinishability and is water and heat resistant. A laminate produced with this resin admixture meets all the physical property requirements for snow ski top surfaces and sidewalls.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention reference may be made to the exemplary embodimentshown in the accompanying drawings in which:

FIG. 1 shows, in three dimensional view, a ski having the melamine modified phenolic resin impregnated paper sheet laminate of this invention as the top surface and sidewall surface; and

FIG. 2 shows, in a cross section, the ski of FIG. 1, including the top surface, sidewall and base laminations of resin impregnated paper sheets.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, FIG. 1 shows a type of snow ski having the melamine modified phenolic resin impregnated laminate of this invention as the ski top surface and sidewall 11.

FIG. 2 shows a cross sectional view of the ski. A lamination of a plurality of bonded, melamine modified phenolic resin impregnated, color pigmented kraft paper sheets made in accordance with this invention, comprise the ski top surface 10, sidewall 11 and can also be used for the base 21.

Generally, skis are made by a sandwich construction, wherein the top surface 10 and bottom base 21 can cover fiber-glass laminations 22. On both sides of the top fiberglass layer'are structural strips 23 of a metal, generally aluminum. These metal strips also serve as top edge protectors above the sidewalls 11. The flexible core 24 of the ski is surrounded by the top surface, base and sidewalls between the top surface and base, and can be of a material such as multi-laminated wood. The lower fiberglass lamination can be covered by the base 21 which can The ski top surface 10, sidewall 11 and base 21 can comprise a plurality of bonded, laminated core sheets 26 of kraft paper, impregnated with a plastic material comprising the melamine modified phenolic resin admixture of this invention. Thesesheets can be assembled and molded under pressures of about 1,200 to 1,500 psi at about 250 to 325F to produce a unitary structure, cooled, and machined, to produce the consolidated refinishable exterior ski surfaces shown as 10,11 and 21in the drawings.

The melamine modifiedphenolic resin system used to impregnate the kraft paper core sheets 26, isa solution of a melamine-formaldehyde, modified, ammonia catalyzed, phenol-formaldehyde resinous admixture. It is the resin admixture that gives the bonded, impregnated, kraft'paper laminates and the ski surfaces, for which they may be used, refinishable properties.

Ordinarily, in the laminating art, melamine-formaldehyde and phenol-formaldehyde resins are'not used in combination because-the melamine resin requires an acid catalyst and the penolic resin requires an alkaline catalyst. We found however, that the combination of both resins were required to give a good combination of properties for snow ski surface applications. The phenol-formaldehyde resin is necessary for toughness and flexibility whereas the melamine-formaldehyde resin is necessary for hardness and high gloss properties. We found that too much phenol-formaldehyde resin in the admixture gave a laminate that would not be buffable and refinishable and that too much melamine-formaldehyde resin in the admixture gave too brittle a laminate. We found the critical ratio to be an admixture of from 10 .to weight percent melamine-formaldehyde resin percent solids) based on phenol-formaldehyde resin (100 percent solids). That is, the admixture must contain 0.1 parts by weight of melamine-formaldehyde resin (100 percent solids) for each 0.9 parts by weight of phenol-formaldehyde resin (l00 percent solids) to give a 10 weight percent ratio of melamine-formaldehyde based on phenolic resin, and the admixture must contain 0.7 parts byweight of melamine-formaldehyde resin (100 percent solids) for each 0.3 parts by weight of phenolformaldehyde resin'(100 percent solids) to give a 70 weight percent ratio of melamine-formaldehyde based on phenolic resin. The preferred ratio is an admixture of from about 20 to 40 weight percent melamine-formaldehyde resin 100 percent solids) based on phenolformaldehyde resin 100 percent solids).

We found a satisfactory weight percent resin to kraft paper ratio to be between 0.75 resin 1.0 paper to 2.0 resin 1.0 paper witha preferred ratio of between about 1.25 resin 1.0 paper to 1.75 resin 1.0 paper.

The following example sets forth a specific melamine modified, phenolic resin admixture that may be employed in a suitable solvent, to impregnate kraft core stock paper sheets for use as refinishable laminates, and especially as refinishable, flexible, exterior ski surfaces that can withstand ski manufacturing processes.

fit between hardened-metal bottom edges formaldehyde solution (about 37 percent solids) and 49 pounds of ammonia (26 Be). The stirrer was started and the mixture was reacted and heated until the batch pounds of spray dried, powdered, .melamine resin- -(about 99- percent solids) was-addedJThe spray dried melamine resin was an unmodified melamine-formaldehyde resin with a mole ratioof formaldehyde to melamine of from 1.5 1 to 2': 1 and-when added, took up water from the phenol-formaldehyde resinous composition. This gave a resinous admixture comprising approximately 25-40 weight percent melamineformaldehyde resin solids based on phenol-formaldehyde resin solids.

After the addition of the melamine-formaldehyde resin, vacuum dehydration was begun, using from 20 to 24 inches of vacuum and enough heat to boil the batch vigorously. The vacuum dehydration was continued for about 1 hour, until about3l7 pounds of distillate was removed. At this point the batch was immediately cooled, the vacuum released and 945 pounds of methanol solvent was added to dilute the resin system toa solution of about 50 weight percent solids content. About 1 percent by weight of a fatty alcohol phosphate release agent was then added, based on the solids content ofthe resin system. 7

This resin solution was used to impregnate a plurality of black pigmented 1 10 pound basis weight kraft paper sheets to a resin to paper ratio of 1.7 1. Three of these impregnated kraft paper sheets (38 inches X 18 inches) were then assembled and molded under 1,200 to 1,500 psi pressure at 300F for minutes to consolidate the assembly to a unitary structure. The resulting product was a black, resin impregnated, bonded laminate about 0.025 inch mils) thick.

Samples of this laminate (6 inches X 9 inches) withstood continuous boiling in water for three weeks without delamination or blistering. Other samples of this laminate withstood temperatures of 350F for 10 minutes without delamination or blistering. The laminate will refinish throughout its entire thickness without showing objectionable lamination lines. The gloss obtained from our laminate after refinishing and buffing was noticeably improved over the gloss from a laminate produced with an unmodified phenolic resin system.

We have also fabricated samples of these laminates (4 inches X 8 inches) to 0.085 inch aluminum sheets using 350F temperatures and 100 psi pressurefor 10 minutes without blistering. We have cut through the entire thickness of these laminates at an approximate angle, sanded the cut surface with fine sandpaper and buffed the cut surface to a high gloss having no color difference throughout the thickness of the laminate, and having no noticeable indications of laminations within the laminate. Laminates produced with this resin system have been fully tested and approved for top surfaces and sidewalls of snow skis.

in addition to using pigmented paper, the color of the laminate can be controlled by the addition of pigments into the resin system before paper impregnation. Usually no more than 1 percent pigment based on resin solids are required. Although the preferred catalyst was ammonia because it gives good water' resistance characteristics, other compatible alkali catalysts such as calcium carbonate and sodium hydroxide may be used. Also, a wide variety of solvent such as ethanol and isopropyl alcohol .among others may be used to dilute the resinous admixture to a suitable solids content of between about 45 to percent solids.

We claim:

1. A resin impregnating solution, for refinishable laminates, consisting. essentially of melamine-formaldehyde resin, phenol-formaldehyde resin and alkali catalyst in a solvent, to provide a solution having a solids content of between about 45 and 60percent, said melamine formaldehyde resin being present in the amount of from 10 to weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids and wherein the melamine-formaldehyde resin comprises a resin having a mole ratio of formaldehydezmelamine of from about 1.5:] to 2:1.

2. The resin solution of claim 1 wherein the catalyst is selected from the group consisting of ammonia, calcium carbonate and sodiurnhydroxide, the solvent is selected from the group consisting of methanol, ethanol and isopropyl alcohol, the melamine resin being present in the amount of from about 20 to 40 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids.

3. A refinishable laminate comprising a plurality of bonded, resin impregnated paper sheets, impregnated with a catalyzed melamine-formaldehyde resin, phenolformaldehyde resin admixture, said admixture compris ing from 10 to 70 weight percent melamineformaldehyde resin solids based on phenol-formaldehyde resin solids, wherein the weight percent resin: paper is a ratio between 0.75 to 2011.0.

4. The 'refinishable laminate of claim 3 wherein the admixture comprises from about 20 to 40 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids.

5. The refinishable laminate of claim 4 wherein the paper sheets are color pigmented kraft paper sheets, the catalyst in the admixture is selected from the group consisting of ammonia, calcium carbonate and sodium hydroxide and the melamine-formaldehyde resin comprises a resin having a mole ratio of formaldehyde melamine of from about 1.5 :lto 2 1.

3. preparing a stacked assembly comprising a plurality of said resin impregnated sheets; and

4. heat and pressure consolidating the assembly into a unitary structure.

7. The method of claim 6 wherein the resin to paper ratio is between about 1.25 1 to 1.75 1, the admixture comprises from about to 40 weight percent melamine-formaldehyde resin solids based on phenolformaldehyde resin solids, the catalyst in the resin admixture is selected from the group consisting of ammonia, calcium carbonate and sodium hydroxide and the melamine-formaldehyde resin comprises a resin having a mole ratio of formaldehyde melamine of fromabout 1.5: 1 to2: 1.

8. The method of claim 7 wherein the admixture contains ammonia catalyst and the stacked assembly is consolidated atbetween about 1,200 to 1,500 psi and 250 to 325F.

9. The method of claim 7 wherein the admixture is in a solution of a solvent selected'from the groupconsisting of methanol, ethanol and isopropyl alcohol and the paper sheets are color pigmented kraft paper sheets.

10. A snow ski comprising a flexible core surrounded by a laminated top surface, base surface, and sidewalls between the top surface and base surface, the improvement being refinishable top surface and sidewall laminations comprising a plurality of bonded, resin impregnated paper sheets impregnated with a catalyzed, melamine-formaldehyde resin, phenol-formaldehyde resin admixture, said resin admixture comprising from 10 to we ight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids and the weight percent resinzpaper is a ratio between 0.75 to 2.0: l .0.

1 1. The snow ski of claim 10 also having a refinishable base surface comprising a plurality of bonded, resin impregnated paper sheets, the sheets of the top surface, base surface and sidewall being impregnated with the admixture, wherein the admixture comprises from about 20 to 40 weightpercent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids.

12. The snow ski of claim 10 wherein the paper sheets are color pigmented kraft paper sheets, the catalyst in the resin admixture is selected from the group consisting of ammonia, calcium carbonate and sodium hydroxide and the melamine-formaldehyde resin comprises a resin having a mole ratio of formaldehyde:melamine of from about 1.5:1 to 2:1. 

2. The resin solution of claim 1 wherein the catalyst is selected from the group consisting of ammonia, calcium carbonate and sodium hydroxide, the solvent is selected from the group consisting of methanol, ethanol and isopropyl alcohol, the melamine resin being present in the amount of from about 20 to 40 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids.
 2. impregnating paper sheets with a solution of the admixture to a resin to paper ratio of between 0.75:1 to 2:1;
 3. preparing a stacked assembly comprising a plurality of said resin impregnated sheets; and
 3. A refinishable laminate comprising a plurality of bonded, resin impregnated paper sheets, impregnated with a catalyzed melamine-formaldehyde resin, phenol-formaldehyde resin admixture, said admixture comprising from 10 to 70 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids, wherein the weight percent resin: paper is a ratio between 0.75 to 2.0:1.0.
 4. heat and pressure consolidating the assembly into a unitary structure.
 4. The refinishable laminate of claim 3 wherein the admixture comprises from about 20 to 40 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids.
 5. The refinishable laminate of claim 4 wherein the paper sheets are color pigmented kraft paper sheets, the catalyst in the admixture is selected from the group consisting of ammonia, calcium carbonate and sodium hydroxide and the melamine-formaldehyde resin comprises a resin having a mole ratio of formaldehyde : melamine of from about 1.5 :1to 2 :
 1. 6. A method of making a refinishable laminate comprising a plurality of bonded sheets comprising the steps of:
 7. The method of claim 6 wherein the resin to paper ratio is between about 1.25 : 1 to 1.75 : 1, the admixture comprises from about 20 to 40 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids, the catalyst in the resin admixture is selected from the group consisting of ammonia, calcium carbonate and sodium hydroxide and the melamine-formaldehyde resin comprises a resin having a mole ratio of formaldehyde : melamine of from about 1.5 : 1 to 2 :
 8. The method of claim 7 wherein the admixture contains ammonia catalyst and the stacked assembly is consolidated at between about 1,200 to 1,500 psi and 250* to 325*F.
 9. The method of claim 7 wherein the admixture is in a solution of a solvent selected from the group consisting of methanol, ethanol and isopropyl alcohol and the paper sheets are color pigmented kraft paper sheets.
 10. A snow ski comprising a flexible core surrounded by a laminated top surface, base surface, and sidewalls between the top surface and base surface, the improvement being refinishable top surface and sidewall laminations comprising a plurality of bonded, resin impregnated paper sheets impregnated with a catalyzed, melamine-formaldehyde resin, phenol-formaldehyde resin admixture, said resin aDmixture comprising from 10 to 70 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids and the weight percent resin:paper is a ratio between 0.75 to 2.0:1.0.
 11. The snow ski of claim 10 also having a refinishable base surface comprising a plurality of bonded, resin impregnated paper sheets, the sheets of the top surface, base surface and sidewall being impregnated with the admixture, wherein the admixture comprises from about 20 to 40 weight percent melamine-formaldehyde resin solids based on phenol-formaldehyde resin solids.
 12. The snow ski of claim 10 wherein the paper sheets are color pigmented kraft paper sheets, the catalyst in the resin admixture is selected from the group consisting of ammonia, calcium carbonate and sodium hydroxide and the melamine-formaldehyde resin comprises a resin having a mole ratio of formaldehyde: melamine of from about 1.5:1 to 2:1. 